Field of the Invention
Embodiments of the present invention generally relate to methods and apparatus for heating substrates, such as semiconductor substrates.
Description of the Related Art
Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and microdevices. One method of processing substrates includes depositing a material, for example, an epitaxial material, on a substrate surface. Deposited film quality is dependent upon several factors, including process conditions such as temperature. As transistor size decreases, temperature control becomes more important in forming high quality films. Temperature control becomes more difficult as throughput increases, particularly due to the demands of rapid substrate temperature increases and decreases (e.g., substrate ramp up and cool down). The substrate heating rate can be increased by adjusting lamp settings. However, substrate cooling is largely dependent on the ambient temperature, which may be difficult or expensive to reduce. To further exacerbate cooling issues, the ambient temperature in close proximity to a substrate is influenced by heated chamber components, particularly a heated lower dome. The absorbed heat radiates to a substrate during cooling, which undesirably extends the time to sufficiently cool a substrate.
Therefore, there is a need for improved cooling.